You're sucking air out of a sealed chamber - presumably with a person inside it.

To me this has "safety critical" written all over it and I'd be extremely cautious about modifying the chamber at all, but I'd be especially cautious about using a DIY hardware and firmware solution to control a safety-critical part of the chamber. What's the worst that could happen if your controller has a logic fault or hardware fault and does the wrong thing at the wrong time?

I only provide help via the forum - please do not contact me for private consultancy.

I was in a one man chamber once, all steel, outward opening, its emergency communication system was a hammer.If you had a problem you could attract attention!

The example above only takes you to about 2 bar above ambient but even so the door locking mechanism is quite susbtantial.At only 2 bar the door hinges and lock have to contain 28lbs/inch2 of pressure on the door. Since it has a 40" dia door dia it has an area of 1256inches2 and so must contain 35,158lbs or 17 tons.

The original post looks very pretty but it cannot be containing much pressure.

I was in a one man chamber once, all steel, outward opening, its emergency communication system was a hammer.If you had a problem you could attract attention!

Sounds like one of the drager coffin jobbies..... they give me the willies!

Theres a trend in sports for hypobaric chambers (for increased red blood cell generation), so I wonder if the widget above is related to that. They typically max out at ~6500M ASL.

Anyway, Im of the opinion sites like this are great when people offer advice on the design/coding. Often people plan to use arduino as a stepping stone/quick prototyping approach, rather than a final design.

It's an "Ovei pod," a phenomenally expensive "micro-environment," fitted with a fancy sound system, a video system, though that system would have to be small by today's standards, and dressed up with some comfy stuff, including its own air conditioner. It looks like the standard model runs about 100K USD. Some sites describe it as a little isolation room specifically for gamers. At that price, it would be less expensive to build a very nicely equipped 60 m2 media room.

I can't find any suggestion that the Ovei pod is able to support a pressure differential in either direction. The mention of gas valves suggests that the OP may be contemplating an oxygen-rich, rather than hyperbaric, environment.

Whatever is contemplated here, it should be done with care, and with a thorough understanding of all the issues and risks involved, or not done at all.

Hyperbaric is more lile pushing air into a sealed vessel. The traget pressure is 4.5 psi and I need to regulate the speed pressure increase. I found some accurate pressure sensors but I was looking to automate the speed of compression and decompression.

That's, what, 30 000 Pa of overpressure?So, 1,3 atmosphere. If my calculation is correct, that's around 85 000 N of force on an opening with 60 cm diameter (something a person might crawl through). I would not mess around with those forces and the thing pictured in your first post most definitely could not withstand that pressure, even if you could seal the door itself.Controlling the pump and a release valve is doable with arduino, but not advisable for this purpose in DIY method.

Once, when I was young, I went into an inflated building. It had no structural integrity, the internal air pressure was simply more than the external and that kept the whole structure upright.

For fire regulations all doors had to open outwards. Of course you do not have a single door in a pressured environment you have a double one.

Yes, yes it was me =( =( =( I opened both doors !!!!

This was not intentional I went through one door then the next.

I know, I know, the entire building started to collapse - it was stupidity of youth and entirely unintentional ( just like the problem with the train which we shall not go into here )

Anyway the overpressure could not have been too great and once the internal fans kicked in to try an stop several hundred people being suffocated a small army of people managed to force one small door closed against the remaining pressure which could have not been to large.